Infectious diseases and viral hemorrhagic fevers (VHFs) pose a significant public health problem, due to the severity of the diseases, high lethality, inter-human contagiousness of certain agents, and lack of effective treatment for most of them.
Some of them are caused by highly infectious RNA viruses from several families including the Flaviviridae (dengue, Yellow fever, West Nile, Japanese encephalitis, Tick-Borne Encephalitis, Hepatitis C viruses), the Togaviridae (Chikungunya, Ross River, Mayaro, Western Equine encephalitis, Eastern Equine Encephalitis, Venezuela Equine Encephalitis viruses) the Bunyaviridae (Crimean-Congo hemorrhagic fever, Rift Valley Fever, Schmallenberg viruses), the Caliciviridae (Hepatitis E virus), the Arenaviridae (Lassa) and the Filoviridae (Ebola, Marburg). Transmission usually occurs by contact with infected animal reservoirs or arthropod vectors. Although the majority of those viruses have a higher occurrence in the tropics and subtropics, the geographic expansion of their natural reservoirs and vectors, and the increase in international travel have made the emergence of these agents in non-endemic areas highly probable. Control of epidemics crucially depends on the rapid detection and accurate identification of the agent, in order to define and implement timely and appropriate action. In this context, it is essential to produce and validate tools for early detection of outbreaks, precise identification of the etiologic agent, and improved disease surveillance.
In this respect, detection of antibodies in body fluids constitutes a major part of the diagnosis of virally induced diseases, autoimmune diseases and the detection of cancer. As a matter of fact, certain antibodies can serve as markers in diagnosis and can lead to prognosis and treatment, as their presence are known to correlate with the outbreak of a pathogen. This is particularly the case for the antibodies targeting viral antigens exclusively.
Current methods for detecting the presence of antibodies include diverse techniques such as immunofluorescence microscopy, chemiluminescence assay, Western blotting, Radio Immuno-Precipitation assay (RIP) and ELISA. For example, the team of Kim H-J. et al. recently developed a competitive ELISA for the detection of antibodies to Rift Valley Fever virus in goat and cattle (The Journal of Veterinary Medical Science, 2011). However, such techniques require measurement of each antibody separately, and thus are not useful for parallel, rapid, and high throughput analysis of multiple antibodies in a single sample of biological fluid. The parallel detection of several antibodies simultaneously may be particularly useful by minimizing the matrix effects that exist between individual assays, such as in ELISAs, because the calibrators and the antibodies are analyzed under the same conditions; it therefore will generate comparable results for the measurement of multiple antibodies present within the same sample.
Complicating the straightforward identification of pathogenically relevant antibodies, however, is that normal sera contain large amounts of natural antibodies which manifest themselves in complex staining patterns (Avrameas S. Immunol. Today 1991). The presence of these natural antibodies can complicate the differentiation of disease-associated antibodies from the complex background of “auto-immune noise”, i.e. naturally occurring autoantibodies. That's why most of previous studies evaluated one or a few specific disease-related antibodies and have screened only a limited number of purified homologous or heterologous proteins as antigens by means of ELISA or RIA. A diagnosis based on these antibodies was impossible to establish. On the other hand, Western blotting has evolved as the most important tool to detect antibodies because it permits simultaneous screening for a wide spectrum of different antigens. A recent new technique, capable of analyzing these complex staining patterns of Western blots simultaneously, is based on digital image analysis. This technique has been successfully used in studies of myasthenia gravis, Graves' disease and experimental uveitis (Zimmerman C W, Electrophoresis 1995). The antibodies may also be detected and measured on a protein chip array using surface-enhanced laser desorption/ionization (SELDI) or matrix assisted laser desorption/ionization mass spectrometry techniques, preferably SELDI mass spectrometry technique (US 2006/166268). Yet, these techniques use large cumbersome equipment that is complex and expensive to maintain, and requires high amount of the biological samples to achieve the detection of antibodies being in a low amount.
In view of the foregoing, there exists a need for addressable systems and methods, which can provide additional improvements in high throughput, cost-effectiveness, and accuracy for molecular diagnosis of antibody-generating diseases. The present invention satisfies these and other needs.